One-step solvothermal synthesis of carbon doped TiO2–MoS2 heterostructure composites with improved visible light catalytic activity†
A carbon doped TiO2–molybdenum sulfide (C-TiO2–MoS2) was synthesized in a single step in an attempt to improve the visible light photocatalytic properties of TiO2. A novel precursor (NH4)2Mo3S13·2H2O was used to incorporate MoS2in situ into TiO2 and the obtained composite had a nearly integrated TiO2–MoS2 structure with few layered MoS2 incorporated more or less uniformly throughout the composite. The composite exhibited improved visible light response owing to C-doping (due to solvent) and the few layered MoS2 sheets. The improved visible light activity was exhibited by the composite for the photodegradation (PD) of rhodamine B (RhB) and 4-aminothiophenol compared to that of the control TiO2. Scavenger studies revealed that the superoxide anion (O2˙−) and singlet oxygen (1O2) are the two dominant reactive oxygen species involved in the visible light PD of RhB. A photoluminescence lifetime measurement showed nearly 4 times faster interfacial charge transfer from RhB to the composite than that of the control TiO2. In addition, decreased charge transfer resistance across the interface was exhibited by the composite and is attributed to the improved charge transport and built-in potential due to MoS2. The synergistic effect of the value-added properties such as improved visible light response and better charge separation of the composites are attributed to the uniform incorporation of few layered MoS2 and effective heterostructure formation between TiO2 and MoS2.